Process of dewaxing oils



Patented Dec. 17, 1940 UNITED STATES PATENT OFFICE PROCESS OF DEWAXING OILS No Drawing. Original application January 4,

1934, Serial No. 705,252. Divided and this application December 31, 1937, Serial No. 182,807

1 Claim.

It has been proposed to remove wa-x from lubricating oil stock by precipitating the wax on the principle of highly diluting the oil in several times its volume of an organic volatile liquid in 5 order to precipitate the wax. Such procedure has the objection of entailing handling by pumps, filters, etc, of impracticable surpluses of nonproductive liquid in addition to the regular burden of throughput of oil. Besides there are aglO gravated losses of the volatile liquid. In accordance with the present invention, it now becomes possible to dewax oils in a manner conform-able to desirable refinery procedure however, and with attainment of products having a pour point considerably below the dewaxing temperature instead of above as customary.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described, and particularly pointed out in the claim, the following description setting forth in detail certain illustrative embodiments of the invention, these being indicative however, of but a few of the various ways in which the principle of the invention may be employed.

The oil to be dewaxed is subjected to the action of an oil-miscible liquid which is a non-solvent for the wax, and in accordance with the present procedure it is in general not necessary to em- 30 ploy such liquid in excess of the volume of the oil, and more usually very materially less than the volume of the oil. Liquids may be employed such as butylamine, creosote oil, cyclohexanol.

The treating liquid may be admixed in any suit- 30 able manner, and by passing the oil through a chilling system, the wax is easily separated in wax filter presses or centrifuges. The chilling temperature may be in the range 80 F. to F., and with most oils it is sufficient if the temperature be -25 F. Most oils pressed at such temperature in accordance with the present process, have a solidifying point of 5 to 15. below 5 the pressing temperature, it being found that wax which otherwise ordinarily would be amorphous and impossible of complete separation even by much lower chilling, is now precipitated out in crystalline form and readily handled in the 10 usual filter press. As contrasted with the usual low temperature process, it is thus readily seen that there is an enormous saving in elimination of ultra-low refrigeration costs, as well as in cost of solvent recovery. As an example: About 15 parts of butylamine is mixed with parts of a wax slop cut from Mid-Continent petroleum, having a viscosity of about sec. S. U. at 210 F., and at a temperature of 60 F. the wax is removed by filtering. The oil so processed at even such a relatively high temperature has an A. S. T. M. pour point of 45 F.

This application is a division of our application Ser. No. 705,252, filed Jan. 4, 1934.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the steps stated in the following claim, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

A process of dewaxing oils, which comprises subjecting the oil to the action of butylamine, chilling, and separating the wax.

ROBERT E. BURK. EVERETT C. HUGHES. 

